def get_formatted_name(first_name,middle_name,last_name):
    """返回整洁的姓名。"""
    full_name = f"{first_name} {middle_name} {last_name}"
    return full_name.title()

musician = get_formatted_name('john','lee','hooker')
print(musician)
def build_person(first_name,last_name,age=None):
    """返回一个字典，其中包含有关一个人的信息。"""
    person = {'first':first_name,'last':last_name}
    if age:
        person['age'] = age
    return person

musician = build_person('jimi','hendrix',age=27)
print(musician)